Records New for Four Deep-Sea Shrimps from the Northeastern Pacificl
ROBERT
A.
WASMER2
IN 1961 the Department of Oceanography of Oregon State University began a long-term ecological study of the northeastern Pacific Ocean off Oregon extending to a distance of 833 km, generally between lat 43 and 46 N. Among the many deep-sea shrimps collected during the course of this study are four species which were taken in hauls made at positions well outside their previously recorded ranges. It is the purpose of this paper to discuss the distributions of these species as they are now known. All of the specimens have been deposited in the collections of the Department of Oceanography, Oregon State University. The collection of the specimens at sea by Department of Oceanography vessels was supported by U.S. Atomic Energy Commission contracts AT(45-1) 1726 and AT(45-1) 2227, Task Agreement no. 12, RLO-2227-T12-2.
ORDER DECAPODA SUBORDER NATANTIA SECTION PENAEIDEA FAMILY PENAEIDAE
Hemipenaetts spinid01'salis Bate, 1881 Hemipenaetts spinidorsalis was originally described from specimens trawled by H.M.S. Challenger from near Tristan da Cunha in the South Atlantic and from near the Philippines in the Pacific (Bate, 1881, 1888). Faxon (1895) recorded the species in the eastern Pacific from off Central America and the Galapagos Islands. It has been taken at depths between 1,867 and 3,749 m (Ramadan, 1938). The two specimens recorded here were taken in a beam trawl to a depth of 3,687 m on 4 June 1970 between lat 4440.7/ N, long 13328.1/ Wand lat 4440.9/ N, long 13324.5/
Manuscript received 8 October 1971. Oregon State University, Department of Zoology, Corvallis, Oregon 97331.
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W. The specimens are a male with a carapace length (postorbital) of 40 mm and a female with a carapace length of 53 mm. H emipenaetts spinidorsalis is closely related to H. carpenteri Wood-Mason. These species share a number of characters which, according to Ramadan (1938), may entitle them to subgeneric recognition: they possess a spine at the end of the carina of the third abdominal segment; the three anterior pereiopods have a much longer carpus than the other species of the genus, and their meri are not flattened; they possess a podobranch on the 12th somite (third pereiopod), an epipodite on the 13th somite (fourth pereiopod), and exopods on all pereiopods. The two specimens possess characters as given by Faxon (1895) and Burkenroad (1936) which distinguish H. spinidorsalis from H. carpenteri: rostrum reaching beyond end of eyes and more than one-fifth the length of the carapace; antennular stylocerite reaching to the tip of externodistal tooth of proximal segment of antennular peduncle; and, in the male, having median blade of bipartite appendix masculina in the form of a long triangular tooth and shorter than the lateral blade, which is concave within and furnished with setae on its distal border (see Faxon, 1895, Plate L, Fig. Ie and 2) .
Plesiopenaetts armattts (Bate), 1881 Plesiopenaetts armattts was originally described from specimens trawled by H.M.S. Challenger from the South Atlantic, the Australian archipelago, the North Pacific (lat 3437/ N, long 14032/ E and lat 3610/ N, long 1780/ E), and from the South Pacific (Bate, 1881, 1888). Subsequently it has been recorded, under one name or another (Burkenroad, 1936, and Ramadan, 1938, discuss the synonomy of the genus and species) , from the Indian Ocean (Alcock, 1901; Ramadan, 1938)
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PACIFIC SCIENCE, Volume 26, July 1972 the Gulf of Panama (Faxon, 1893, 1895), and has subsequently been recorded from the Indian Ocean (Alcock and Anderson, 1896; Anderson, 1896; Alcock, 1899, 1901; Balss, 1925) and Atlantic Ocean (Balss, 1925; Holthuis, 1951; Springer and Bullis, 1956; Figueria, 1957; Fisher and Goldie, 1961; Crosnier and Forest, 1968; Foxton, 1970). It has been recorded from hauls made to 3,200 m. Although Forss (1966) figured and discussed a damaged specimen of Systellaspis cristata from off Oregon (taken at night from a depth range of 1,000-500 m, on 20 October 1964, between lat 4428' N, long 12520' Wand !at 4434.5' N, long 12531.4' W), it is nevertheless satisfying to record the species from the area again. Two additional specimens have been identified from OSU oceanography collections. The first, a female with a carapace length of 11 mm, was taken in an Isaacs-Kidd midwater trawl towed at night through the depth range 200-0 m, on 20 July 1961, between lat 4614.4' N, long 12440.4' Wand lat 4614.4' N, long 12433.6' W. A second female specimen (carapace length 11.5 mm), also from an Isaacs-Kidd midwater trawl, was taken during a daylight tow on 23 September 1969, at a station located 65 miles off the central Oregon coast (lat 4439.2' N, long 12539.8' W), from a depth range of 500-0 m. Both specimens agree with the description of the species given by Holthuis (1951).
DISCUSSION
and Atlantic Ocean (Smith, 1884; Faxon, 1896; Bouvier, 1905, 1908; Milne-Edwards and Bouvier, 1909; Sund, 1920; Roberts and Pequegnat, 1970). It has been taken at depths between 750 and 5,400 m. The present specimen was taken in a beam trawl to a depth of 3,724 m on 3 June 1970 between lat 4440.2' N, long 13335.7' W and lat 4439.5' N, long 13338.3' W, and so is the first record of the species from the northeastern Pacific. It is a female with a carapace length of 77 mm (combined rostrum and carapace length of 127 mm). The specimen agrees with descriptions of the species, possessing characters given by Burkenroad (1936) and Ramadan (1938) which distinguish it from other species in the genus: last four abdominal terga carinate dorsally, a mobile spine on merus of first and second pereiopods, and a strong ischial tooth on first pereiopods.
SECTION CARIDEA FAMILY OPLOPHORIDAE
Acanthephyra micropthalma Smith, 1885 Acanthephyra micropthalma was originally described from specimens trawled from the western Atlantic off the east coast of the United States (Smith, 1885, 1886). Elsewhere in the Atlantic it has been recorded from off Portugal by Coutiere (1911) and from southwest of the Azores by Sivertsen and Holthuis (1956). Alcock (1901) recorded it from the Bay of Bengal. In the Pacific it has only been recorded from the Celebes Sea and the southern Pacific by Bate (1888) as A. longidens Bate. It has been taken at depths between 2,000 and 4,700 m (Sivertsen and Holthuis, 1956). The present specimen was taken in a beam trawl to a depth of 3,655 m on 1 June 1970 between lat 4427' N, long 13214' Wand lat 4424.6' N, long 13212.9' W, and so is the first record of the species from the northeastern Pacific. The specimen, which is a female with a carapace length of 22 mm, agrees with the descriptions and figures of the species in the literature. Systellaspis cristata (Faxon), 1893 Systellaspis cristata was originally described from specimens taken by the Albatross from
The actual depth of capture of specimens taken by open trawls and dredges is always in doubt since these may take specimens during descent and ascent, in addition to the normal samples taken on the bottom. Because of this, it is proper to ask whether the shrimps Hemipenaetts spinidorsalis, Plesiopmaet's armatus, and Acanthephyra micropthalma, which were collected only by bottom trawls, are benthic or pelagic. Examination of foregut contents from the specimens of Hemipmaet/s spinidorsalis and PlesiopenaettS armatus showed the following to be present: calcareous shell fragments; Radiolaria; Foraminifera; and unidentified crustacean remains. In addition, the foregut contents from
New Records for Shrimps from the Northeastern Pacific-WASMER
Hemipenaeus spinidorsalis included small sections of brown tube composed of cemented debris, whereas those from Plesiopenaeus armatus included fairly large pieces of skeletal plates and spines from ophiuroid arms, several segments of a hollow calcareous tube, and a large amount of what appeared to be sediment. The evidence presented by the foregut contents from these specimens thus indicates that they had resorted to the bottom to feed. This conclusion, along with the fact that all the previous capture records for the two species are only from trawl or dredge samples, suggests a benthonic existence for both Hemipenaeus spinidorsalis and Plesiopenaeus armatus. Although most adult Penaeidae, whether neritic or oceanic, are benthonic, a pelagic existence does occur sporadically throughout the family, and it is possible behavior that of both types is found together in certain abyssal species of the family (Burkenroad, 1936). Conceivably then, specimens of Hemipenaeus spinidorsalis and Plesiopenaeus annattlS might swim up from the bottom at times, so that they might be taken by pelagic hauls. That these species do have a strong swimming capability is suggested by their long and well-developed pleopods. Burkenroad (1937) pointed out, however, that "the term benthonic when applied to Decapoda Natantia, can refer at most to a vital dependence upon the bottom, rather than to an entirely substratal existence." If this is accepted, then the apparent obligatory resort to the bottom to feed by the specimens of Hemipenaeus spinidorsalis and Plesiopenaeus armatus would bring these species within the range of the term, even though at times they might conceivably be found in the water column. The environmental characteristics of the sediments and bottom water at the station where Hemipenaeus spinidorsalis and Plesiopenaeus armatus were taken are as follows (A. G. Carey, personal communication): sediments (0.3 percent sand, 62.1 percent silt, and 37.7 percent clay); bottom water (1.55C, 2.98 ml/liter O2 , and 34.66 %0 salinity). The situation is somewhat different in the case of Acanthephyra micropthalma. This species, together with SysteUaspis cristata, belongs to a family (Oplophoridae) which appears to
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be exclusively pelagic in habitat (Kemp, 1939). Examination of the published capture records for this species reveals, however, that all except one are from trawl or dredge samples. The exception is that reported by Coutiere (1911) who recorded the species (as Acanthephyra longidem Bate) from a "Bouree net" towed at a high rate of speed. The samples collected with this net consisted entirely of shrimps considered to be pelagic, the vast majority belonging to the Oplophoridae. The foregut contents of the present specimen consist solely of unidentified crustacean remains, with a complete lack of any remains indicating bottom foraging, as was the case in the other two species. In addition, the pereiopods do not appear to show any special adaptations for a benthic existence, but appear to be similiar to those of other members of the genus. Thus, it can be concluded that A. micropthalma is a species which is probably not confined to the immediate neighborhood of the bottom, but which does show structural evidences of inhabiting very great depths (very poorly developed eyes and soft integument). The presence of this species in the sample thus would be due to its having been caught either as the trawl descended or ascended. If this is the case, the vertical distribution of the species is almost certainly below 1,000 m, inasmuch as it has never been taken in the many midwater trawls from 0-1,000 m which have been taken off Oregon.
LITERATURE CITED ALCOCK, A. 1899. A summary of the deepsea zoological work of the Royal Indian Marine Survey Ship "Investigator" from 1884 to 1897. Sci. Mem. Med. Offrs. Army India 11:1-49. - - - . 1901. A descriptive catalogue of the Indian deep-sea Crustacea Decapoda Macrura and Anomala in the Indian Museum. Indian Museum, Calcutta. 286 p. ALCOCK, A., and R. S. ANDERSON. 1896. Illustrations of the zoology of the Royal Indian Marine Surveying Steamer "Investigator," Crustacea, pt. 4, pI. 16-17. ANDERSON, R. S. 1896. An account of the
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- - - . 1895. Reports on an exploration off the west coasts of Mexico, Central and South America, and off the Galapagos Islands, etc. XV. The stalk-eyed Crustacea. Mem. Mus. Compo Zoo1. Harv. 18:1-292. - - - . 1896. Reports on the results of dredging . . . in the Gulf of Mexico and the Caribbean Sea, and on the east coast of the U.S., 1877 to 1880, by the US. Coast Survey Steamer "Blake." Bull. Mus. Camp. Zool. Harv. 30 (3) :154-166. FIGUEIRA, A. J. G. 1957. Madeiran decapod crustaceans in the collection of the Museu Municipal do Funchal. I. On some interesting deep-sea prawns of the families Pasiphaeidae, Oplophoridae and Pandalidae. Bol. Mus. Funchal 10 (25) :22-51. FISHER, L. R., and E. H. GOLDIE. 1961. New records for two deep-sea decapods. Crustaceana 2 (1) :78-79. FORSS, C. A. 1966. The oplophorid and pasiphaeid shrimp from off the Oregon coast. Ph.D. thesis, Oregon State Univ. Corvallis. FOXTON, P. 1970. The vertical distribution of pelagic decapods (Crustacea: Natantia) collected on the SOND cruise, 1965. I. The Caridea. J. Mar. BioI. Ass. UK. 50 (4): 939-960. HOLTHUIS, L. B. 1951. The Caridean Crustacea of tropical west Africa. Atlantide Rep. 2 :7187. KEMP, S. W. 1939. On Acanthephyra purpurea and its allies (Crustacea Decapoda; Hoplophoridae). Ann. Mag. Nat. Hist., ser. 11, 24:568-579. MILNE-EDWARDS, A., and E. L. BOUVIER. 1909. Reports on the results of dredging in the Gulf of Mexico ... by the US. Coast Survey Steamer "Blake." XLIV. Les Peneides et Stenopides. Mem. Mus. Compo Zool. Harv. 28 (3) :181-274. RAMADAN, M. M. 1938. Crustacea: P...